1. Field of the Invention
This invention relates to a process for isomerizing epoxides to ketones.
2. Description of the Related Art
The isomerization of epoxides to ketones is known in the art. U.S. Pat. No. 2,799,708 teaches that epoxides having from 4 to 16 carbon atoms wherein the epoxide group is joined to at least one secondary carbon atom are isomerized to ketones by contacting the epoxide with a metal from groups IB and VIII of the periodic table supported on an activate carbon base at a temperature of from about 200.degree. C. to about 500.degree. C. Hydrogen is not used in the process. U.S. Pat. No. 3,009,959 teaches that epoxides having from 4 to 16 carbon atoms wherein the epoxide group is joined to at least one secondary carbon atom are isomerized to ketones by contacting the epoxide at a temperature of from about 200.degree. C. to about 500.degree. C. and at a pressure of 150-350 psig in the presence of hydrogen at 0.5-6.0 hydrogen-epoxide mole ratio with copper on an activated carbon base. U.S. Pat. No. 3,321,515 teaches a method for making fluorinated ketones by contacting fluorinated epoxides with a catalytic amount of an alkali metal fluoride. European Patent Application 0192298 teaches a method for the gas phase isomerization of a saturated alkene or cycloalkene oxide to the corresponding ketone using a catalyst that contains a noble metal of group VIII in the periodic table deposited on a basic support in the presence of hydrogen.
The mechanism of the gas phase isomerization of epoxides over noble metal catalysts has been reported in J. Catal., 63, 364 (1980), J. Catal., 61, 1 (1980), J. Catal., 68, 209 (1981), J. Catal., 68 , 252 (1981), J. Catal., 71, 331 (1981), J. Catal., 100, 39 (1986), J. Chem. Soc., Faraday Trans., 83(8), 2359 (1987), J. Mol. Catal., 44, 337 (1988), J. Chem. Soc., Chem. Comm., 744 (1979), Acta Chim. Acad. Scient. Hung. Tomus, 76(4), 417 (1973), React. Kinet. Catal. Lett., 29(2), (1985)
Liquid phase epoxide-to-ketone isomerizations have been accomplished using various types of acidic catalysts such as BF.sub.3 -etherate as taught in J. Am. Oil Chem. Soc., 42, 126 (1965) and Fette Seifen Anstrichmittel #3, 109 (1984) teaches that terminal and inner olefin epoxides can be isomerized to the corresponding carbonyl compounds by reaction with acidic catalysts such as HI.
None of the prior art methods discloses isomerization of an epoxide in the liquid phase using a palladium catalyst. None of the prior art methods discloses isomerization of an epoxide having a ester, ketone, or ether functionality in the liquid phase or gas phase using a palladium catalyst at relatively low temperatures and at atmospheric pressure.